If you want to upgrade/downgrade your mincraft version with this mode, you need to delete config too because of their different structures on different versions.
Ive downgraded from 1.20.1 to 1.18.1 and got couldnt launch the game before removing config
1-20-1config.json
1-18-1config.json
latest.log

Hi, this is normal.

Config should work when upgrading, but downgrading unfortunately isn’t supported